1. Field of the Invention
The present invention relates to the mixing of a solid particulate material with a fluid. More particularly the present invention relates to an improved mixing device for mixing an abrasive such as sand with a fluid such as air.
2. Description of Prior Art
The prior art has known various means and methods for mixing a solid particulate material with a flowing fluid. One important aspect of mixing a solid particulate material with a fluid concerns the art of sand blasting wherein an abrasive such as sand is mixed with a flowing fluid such as air. In the prior art sand blasting apparatii, sand from a pressurized vessel is introduced into a stream of flowing high pressure air. The introduction of the sand into the stream of flowing high pressure air is generally accomplished by a mixing device such as a T-fitting. The stream of high pressure air is passed through the T-fitting parallel to the longitudinal dimension of the T-fitting. The sand from the pressurized vessel is introduced into the stream of flowing high pressure air through a side opening in the T-fitting. Since the sand from the pressurized vessel is introduced through the side opening of the T-fitting, the sand must be redirected through an angle of ninety degrees before the sand is flowing in the same direction as the direction of flow as the high pressure air. The redirection of the sand within the T-fitting results in a substantial erosion of the internal channels of the T-fitting and ultimately results in the failure of the T-fitting.
The useful life of the T-fitting in a sand blasting apparatus is critical to the operating efficiency of the sand blasting apparatus. If the useful life of the T-fitting is relatively short, the operating efficiency of the sand blasting apparatus is relatively low since the sand blasting operation must be terminated during the replacement of the T-fitting. Such inefficiency is extremely costly since it not only affects the operating efficiency of the sand blasting apparatus per se, but also affects the operating efficiency of the object being sand blasted. For example, during the sand blasting of a commercial or a military ship, the ship is unavailable for normal commercial or military service resulting in a very substantial cost to the commercial business or the military service.
Therefore, an object of the present invention is to provide an improved mixing device having a long useful life for increasing the operating efficiency of the sand blasting apparatus and consequently the operating efficiency of the object being sand blasted.
Another object of the present invention is to provide an improved mixing device having a novel means for introducing the sand from the pressurized vessel through a side opening of the T-fitting of a sand blasting apparatus.
Another object of the present invention is to provide an improved mixing device having novel means for redirecting the sand from the side opening in the T-fitting to flow in the same direction as the high pressure flowing air.
Another object of the present invention is to provide an improved mixing device having novel means for decreasing the erosion of the internal channels of the T-fitting and upon continued use of the sand blasting apparatus.
Another object of the present invention is to provide an improved mixing device having a novel means for introducing the sand from the pressurized vessel through the side opening of the T-fitting at an acute angle relative to the direction of flow of the high pressure air enabling the erosion of the T-fitting to be distributed over a region of the T-fitting member during prolonged use of the sand blasting apparatus.
Another object of the present invention is to provide an improved mixing device having a novel sacrificial insert within the T-fitting for reducing the possibility of failure of the T-fitting.
Another object of the present invention is to provide an improved mixing device having a novel replaceable sacrificial insert within the T-fitting for enabling the reuse of the same T-fitting.
Another object of the present invention is to provide an improved mixing device which may be used with conventional sand blasting apparatii without modification.
The foregoing has outlined some of the more pertinent objects of the present invention. These objects should be construed to be merely illustrative of some of the more pertinent features and applications of the invention. Many other beneficial results can be obtained by applying the disclosed invention in a different manner or modifying the invention within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the summary of the invention and the detailed description describing the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.